1. Field of the Invention
The present invention relates, generally, to vehicle seat assemblies and, more particularly, to a vehicle seat assembly with a biased headrest.
2. Description of the Related Art
Conventional vehicle seat assembly designs typically include a seatback assembly, a lower seat cushion, a recliner mechanism, a manual or power adjustment mechanism for adjusting the position of either the seat back or seat cushion, as well as a number of safety features including occupant restraint devices such as seatbelts. The vehicle seat assembly also typically includes a headrest mounted at the top or upper end of the seat back.
In the context of vehicle seating design, there is an ongoing effort to improve the safety of the vehicle occupant in the event of a collision. More specifically, there is an ongoing effort to provide safety mechanisms that reduce the chance of injury to the passenger's head and neck area. In the event of a rearward impact, the occupant is forced against the seat and can experience a very large energy pulse. In such circumstances, the pelvis and lumbar regions of the occupant generally exert more force, initially, on the seatback than do the thoracic or shoulder regions of the occupant. This initial load may cause a separation between the seatback and the thoracic, neck, and head regions of the occupant. Depending on the force of the rear impact, this separation can be quickly and violently closed by a following movement of the upper torso, neck, and head of the passenger toward the seatback in an event commonly known as “whiplash.” The headrest of the seat assembly is designed to support the passenger's thoracic, neck, and head region during such an event to thereby reduce whiplash injuries.
There is also an ongoing effort to improve configurable interior seating systems that include seats that are moveable relative to the vehicle floor. For instance, in some seat assemblies conventionally referred to as “fold and tumble” seats, the seat back is moveable between an upright, generally vertical position, a first stowed position in which the seat back is folded into a generally horizontal position atop the lower seat cushion, and a second stowed position in which the seat back is moved with the seat cushion into a generally vertical position. These seat assemblies can be moved depending on the cargo or persons to be transported.
In some cases, the headrest limits the movement of the seat assembly because the headrest interferes with the vehicle floor or other surrounding structure. Thus, in partial response to this problem, headrests have been designed that are moveable in relation to the seat back. Once the headrest is moved, the headrest avoids interference with the vehicle floor or other surrounding structure, and the seat back can move over a larger range of motion.
While seat assemblies with movable headrests of the prior art have functioned adequately for their intended purposes, certain problems still remain. For instance, when the seat back is moved back from its stowed position to its upright position, the headrest remains out of position and must be manually raised into position for effectively supporting the occupant's thoracic, neck, and head region in the event of a vehicular collision. This can be an inconvenience for the occupant. Also, the occupant may forget to manually raise the headrest, and as such, the headrest is unable to properly support the occupant's thoracic, neck, and head region in the event of a vehicular collision. Therefore, there is an ongoing need for an improved seat assembly having a headrest that is moveable to avoid interference with other portions of the vehicle when stowed and that automatically moves into its raised position once the seat assembly is moved from its stowed position to its upright position such that the headrest can support the occupant's thoracic, neck, and head region.